Fluid control device



May 22, 1951 M. CARLSON FLUID CONTROL DEVICE Filed Dec. 9, 1948 45 63INVENTOR.

m I i tin Carlson mar ' control be fully automatic.

Patented May 22, 1951 FLUID CONTROL DEVICE Martin Carlson, Brookfield,111;, assignor to- George W. Houlsby, Jr.; Chicago, Ill.

Application December 9, 1948 Serial No. 64,383

- 4 Claims.

My invention relates to control systems. It relates more in particularto a fluid control combination utilizable in installations of a type inwhich a piston or the like should have a relatively rapid initialmovement and a retarded final movement.

In fluid control devices, of which the Door Check Mechanism disclosed inmy copending application Serial No. 20,515, filed April 12, 1948, isillustrative, it is desirable that the movement of the hydraulic pistonbe relatively rapid during the first part of its movement and relativelyretarded during the final portion of its movement. It is also desirablethat the necessary Another example of a system in which the same generaltype of control is desirable is a hydraulic lifting jack in which fluidis pumped into a cylinder to move a piston during the lifting operationand released from the cylinder during the lowering operation. In the useof such jacks, it is the practice to control the hydraulic fluid byhand; but such control is frequently entirely unsatisfactory. I am awarethat means for the automatic control of fluid flow in such devices hasbeen suggested, but in general it has involved the control of the areaof an orifice and it is well known that such control is accomplishedonly with great difliculty and frequently the results are unsuccessful.I

The principal object of m invention is the provision of an improvedcontrol of the character identified. Still another object is theprovision of a fluid control device which may be associated with anyworking piston of the type usually in hydraulic systems.

The drawings show one specific embodiment of my invention in which Fig.1 is a fragmentary sectional view of a piston through a portion of acylinder and piston showing the piston in an expanded position;

Fig. 2 is a similar view showing the piston advanced substantially itsmaximum distance within the cylinder;

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 1 looking inthe direction of the arrows;

Fig. 4 is a fragmentary enlarged sectional view taken through a portionof the valve comprising my invention; and

Fig. 5 is a sectional view showing a modified structure in whichadjustment of the point of complete cut-off of one outlet port ispossible.

In Figs. 1 to5, inclusive, I have shown the invention in relativelysimple form associated with a Cylinder I0 and IJiStbn ll reciprocable'therein. The Cylinder head is provided with a fluid intake l2 and a pairof outlet passageways v I3 and I4. Passageways [3' and [4' are con--*from the passageways l3 and reservoir.

the'passageways l3 and M and are adjustable nec'ted at 16 and adischarge passageway I! is provided from the said cross passageway l'6'.This is illustrative of a simple arrangement, but obviously the fluiddischarge could be directly Hi to a single Tapered plugs I8 and 19project into to control the cross-sectional area between the passagewaysl3 and 14 and the cross passage -way It, respectively. Thus, bycontrolling the positions of the plugs l8 and IS, the effective area ofthe two discharge controlled.

It will be recalled that my invention may be employed in a hydraulicsystem in which fluid is drawn into the cylinder l0 by the action of thepiston, or in which the piston H may be raised against a load by forcinghydraulic fluid into the cylinder beneath the piston. It is withoutsignificance so far as my invention is concerned, therefore, whether theinlet I2 is connected to a pump system for receiving fluid underpressure or to a static sump system in which fluid is merely madeavailable for delivery on the suction stroke of the piston. In any case,

the inlet passageway is provided with a seat 21 the ball 22 is heldagainst its seat and ejection of fluid through the inlet passageway isprevented. The fluid is, therefore, forced to pass only through theoutlet passageways 'I3 and [4* and hence its flow may be controlled.

Disposed centrally of the passageway I4 I provide a valve pin 24 having'a tapered end 26 and shoulder 21 adapted to fit snugly against a seat 28formed at the upper edge of passageway l4. The pin 24 is carried by aguide 29 which is threaded in a bottom opening 3| in the piston, and hasa head 32 engaged by a compression spring 33. The compression spring 33holds the valve pin 24 at the bottommost position when the piston is inelevated position, but

can be compressed as indicated in Fig. 2 when shoulder 21 engages theseat 28. Preferably the valve pin 24 is supported axially of the pistonI I so that even though the piston may be rotated slightly, the taperedportionifi willalways be in alignment with the passageway l4.

passageways may be The operation of the device is as follows. When thepiston is in elevated position and the cylinder below the piston isfilled with fluid either by suction or under pressure, as in a hydraulicjack or like device, the valve pin 24 is at its lowermost position asshown in Fig. 1. When the piston moves downwardly under load, hydraulicfluid will pass through both passageways !3 and I4 in total amountdetermined by the cross-sectional area of such passageways, or, whenadjustable means 18 and 19 are employed, by the position to which suchmeans has been adjusted. As the piston moves downwardly, the passageway14 is first gradually restricted through the entrance of the taperedportion 26, and of course this tapered portion can be shaped in anydesired manner to provide as much of a gradual restricting of the fiowas desired. When the valve pin has been seated entirely with theshoulder 21 on the seat 28, however, passage of fluid through thepassageway I4 is substantially completely arrested. At this time,however, the piston is still permitted to descend because the spring 33may be compressed, but the flow of fluid from the cylinder will begreatly decreased because it is passing only through the passageway l3.In this manner, by properly designing the parts, almost any type ofcontrol and deceleration which could possibly be required may beprovided for. It will be understood also that by providing more than onevalve pin 24, operating at different times in a cycle, deceleration canbe further expanded as desired.

. In the modified form shown in Fig. 5, the cylinder 36 has a piston 31reciprocable therein, and is provided with an inlet passageway 38 andoutlet passageways 39 and il generaly similar to those provided in thefirst described embodiment. The outlet passageway 4i, however, isdisposed in an adjustably positioned plug 42 and has radial ports 43communicating with annular recess 44 which is generally in alignmentwith passageway 46. Passageway 46 connects with passageway 41 in which atapered plug 48 isadjustable. A similar tapered plug 49 is disposed inthe outlet passageway 38 so that by the adjustment of the tapered plugs48 and 49 the effect of cross-sectional area of the two outletpassageways can be varied. A cross passageway interconnects the outletpassageway 39 and the passageway 41, and a discharge passageway 52,corresponding generally to the discharge passageway I! previouslydescribed, leads from the cross passageway 5|.

The piston 31 carries a tapered valve pin 53 which is reciprocable inguide 54 and has a head 56 engaged by spring 51. The pin 53 has atapered end 58 which extends into the outlet passageway 4i and ashoulder 59 adapted to fit against a seat 6| to substantially completelyclose the passageway 4|.

The device, as shown in Fig. 5, functions substantially the same as thepreviously described device except that the position at which thetapered end of the pin begins to close the passageway 4| and theposition at which this passageway is substantially completely closed offis made adjustable by turning the plug 42. Suitable means is utilized toprevent leakage of fluid past the plug 42 and I have found that a smallring 62 of neoprene or other synthetic rubber or like material resistantto attack by oils and greases may be used. All that is necessary is toprovide an annular groove on the exterior of the plug and engagev thering 62 therein, the parts 4' being so arranged that there is someslight compression of the ring 62 when assembly has been completed. Infunctioning as an inlet, the passageway 38 may be suitably provided witha ball check 63 and usual means referred to hereinabove for bringinghydraulic fluid into the cylinder and receiving discharge therefrom may,of course, be used.

I have described my invention in simple form and in detail for theguidance of those skilled in the art; it is understood that theinvention is defined by the scope of the claims.

What I claim as new and desire to protect by Letters Patent of theUnited States is:

1. A hydraulic check mechanism comprising means forming a cylinder withan end wall, a piston fitted to said cylinder, said end wall having anopening therethrough forming an inlet to said cylinder, means forming aone Way check valve in said opening to prevent outward flowtherethrough, said end wall having a second opening therein coaxial withsaid cylinder with the inner end of said opening forming a valve seat,said piston having a cavity formed in the end thereof in alignment withsaid valve seat, a valve pin disposed partially within said cavity withthe end projecting therefrom, said end being tapered to a point andhaving an abrupt annular shoulder at the large end of said taper, saidlarge end being smaller than said valve seat and said shoulder beinglarge enough to close said second opening at said seat, means forretaining said pin in said cavity while permitting limited axialmovement thereof, resilient means aid cavity for urging said pin to itsoutward limit, athird opening in said end wall, said second and thirdopenings being connected by a transverse passage Within said end wall,an outlet passage leading from said connected second and third openings,adjustable valve means fitted to the outer end of said second passageand adjustable to control the flow rate between said second passage andsaid transverse passage and similar adjustable valve means fitted to theouter end of said third passage and adjustable to control the flow ratebetween said third passage and said transverse passage.

2. A hydraulic check mechanism comprising means forming a cylinder withan end wall, a piston fitted to said cylinder, said end wall having anopening therethrough forming an inlet to said cylinder, means forming aone way check valve in said opening to prevent outward flowtherethrough, said end wall having a second opening therein coaxial withsaid cylinder, a valve seat forming member threaded into said secondopening with said seat facing inward, said piston having a cavity formedin the end thereof in alignment with said valve seat, a valve pindisposed partially within said cavity with the end projecting therefrom,said end being gradually tapered to a point and having an abrupt annularshoulder at the large end of said taper, said large end being smallerthan said valve seat and said shoulder being large enough to close saidsecond opening at said seat, means for retaining said pin in said cavitywhile permitting limited axial movement thereof, resilient means in saidcavity for urging said pin to its outward limit, a third opening in saidend wall, said second and third openings being connected by a transversepassage within said end wall, an outlet passage leading from saidconnected second and third openings,

ladjustable valve means fitted to the outer end of said second passageand adjustable to control the flow rate between said second passage andsaid transverse passage and similar adjustable valve means fitted to theouter end of said third passage and adjustable to control the flow ratebetween said third passage and said transverse passage.

3. A hydraulic check mechanism comprising means forming a cylinder withan end wall, a piston fitted to said cylinder, said end wall having anopening therethrough forming an inlet to said cylinder, means forming aone way check valve in said opening to prevent outward flowtherethrough, said end wall having a second opening therein coaxial withsaid cylinder, a valve seat forming member threaded into said secondopening with said seat facing inward, said piston having a cavity formedin the end thereof in alignment with said valve seat, a valve pindisposed partially within said cavity with the end projecting therefrom,said end being gradually tapered to a point and having an abrupt annularshoulder at the large end of said taper, said large end being smallerthan said valve seat and said shoulder being large enough to close saidsecond opening at said seat, means for retaining said pin in said cavitywhile permitting limited axial movement thereof, resilient means in saidcavity for urging said pin to its outward limit, an outlet passageleading from said second opening, adjustable valve means to control theflow rate through said second opening, and means accessible from outsidesaid cylinder for rotating said seat forming member to determine theposition of said piston at which said valve pin enters said seat formingmember.

4. In a hydraulic check device, means forming a dash pot cylinder andpiston combination, said combination having an inlet opening ofsuflicient size to permit substantially uninhibited inflow of hydraulicfluid into said cylinder when said combination is expanded, said inlethaving a check valve to prevent outflow therethrough, means forming anoutflow passage leading from said cylinder, said passage having anadjustable valve therein to limit the rate of fluid flow therethrough tocause slow but uniform rate collapsing of said combination near thecollapsed end of its stroke, a second outflow passage, valve means foradjusting the flow rate through said second passage so as to permitrapid but controlled collapsing movement of said combination when saidcombination is near the expanded end of its stroke, a gradually taperedvalve pin adapted to approach, enter and finally seal said secondpassage as said combination collapses so as to give a slow transition inthe collapsing rate from said rapid to said slow but uniform rate, saidvalve pin having a gradually tapered end portion with an abrupt annularseating surface at the inner end thereof, saidtapered portion beingsmaller at all diameters than said second passage and said seatingsurface being larger than said second passage, and resilient mountingmeans for said valve pin to permit continued collapsing movement of saidcombination after said annular surface is seated in said second passage.

MARTIN CARLSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,891,312 Knecht Dec. 20, 19322,163,440 Tomkins June 30, 1939 FOREIGN PATENTS Number Country Date361,122 Great Britain Nov. 19, 1931 478,566 Germany July 5, 1929

